Non-pneumatic tires which comprise an annular tread portion for coming into contact with a road surface, an annular inner portion disposed inward of the tread portion in a tire radial direction and a plurality of connecting portions connecting the tread portion and the inner portion have been known. The tread portion generally includes a portion formed of rubber or resin. In such a non-pneumatic tire, when traveling, a large hysteresis loss occurs in the tread portion by being repeated compressive and tensile deformation of the tread portion. Hysteresis loss generates heat energy that heats the tread portion. The heat tends to degrade the tread portion and will cause deterioration in durability of the non-pneumatic tire.